Abstract
Boron (B) as borate cross-links pectic polysaccharides at rhamnogalacturonan II regions, thereby contributes to building the cell wall structure. We previously showed that B deprivation immediately induces Ca2+ influx and upregulation of stress-reponsive genes in suspension-culture tobacco BY-2 cells. In an effort to understand the molecular mechanism of such quick responses, we have characterized early responses of Arabidopsis roots to B deprivation.
In the Arabidopsis roots deprived of B for 1 h, elongation zone was specifically stained with Evans blue dye. The same region was also found to accumulate reactive oxygen species (ROS). These results suggest that in Arabidopsis elongating cells are particularly susceptible to B deficiency. Semiquantitative RT-PCR analyses revealed that deprivation of B for 1 h induced a similar set of stress-responsive genes in both Arabidopsis roots and tobacco BY-2 cells. Employing the expression of these genes as the marker, we are going to characterize the mutants of the proteins that are possibly involved in B-deficiency stress signal transduction.
